Purification, characterization and physiological role of sucrose synthase in the pea seed coat (Pisum sativum L.)

• Published in: Planta 1997, Vol.201 (2), p.128-137
• Main Authors: Dejardin, A, Rochat, C, Maugenest, S, Boutin, J.-P. (INRA, Versailles (France). Lab. du Metabolisme et de la Nutrition des Plantes)
• Format: Article
• Language: English
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Agronomy. Soil science and plant productions; ALMIDON; AMIDON; Base Sequence; Biological and medical sciences; BIOLOGICAL DEVELOPMENT; Chromatography; Complementary DNA; Corn; DESARROLLO BIOLOGICO; Developmental stages; DEVELOPPEMENT BIOLOGIQUE; DNA, Plant; Economic plant physiology; EMBRIONES VEGETALES; EMBRYON VEGETAL; Embryos; ENZIMAS; Enzymcharakterisierung; ENZYME; ENZYMES; ENZYMIC ACTIVITY; Enzymreinigung; Fructification and ripening; Fructification, ripening. Postharvest physiology; FRUCTOFURANOSIDASA; FRUCTOFURANOSIDASE; Fundamental and applied biological sciences. Psychology; Gels; Gene Expression; Glucosyltransferases - chemistry; Glucosyltransferases - genetics; Glucosyltransferases - isolation & purification; Glucosyltransferases - physiology; GRAINE; Growth and development; Markierung; Molecular Sequence Data; NUCLEOTIDE SEQUENCE; Peas; PISUM SATIVUM; Pisum sativum - enzymology; Pisum sativum - growth & development; PLANT EMBRYOS; Plant physiology and development; Plants; radioaktive Markierung; SACCHAROSE; Saccharosephosphatsynthase; Saccharosesynthase; Samenhuelle; saure Invertase; SECUENCIA NUCLEOTIDICA; SEEDS; Seeds - enzymology; SEMILLA; SEQUENCE NUCLEOTIDIQUE; STARCH; Starch - metabolism; Starches; SUCROSA; SUCROSE; Sucrose - metabolism; TECHNIQUE DES TRACEURS; TECNICAS DE TRAZADORES; Testa; TRACER TECHNIQUES; Vegetative and sexual reproduction, floral biology, fructification
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/BF01007697

The seed coat is a maternal organ which surrounds the embryo and is involved in the control of its nutrition. This study with pea (Pisum sativum L.) was conducted to understand more fully the sucrose/starch interconversions occurring in the seed coat. The concentrations of soluble sugars, the starch content, and the activities of the sucrose-metabolizing enzymes, sucrose synthase (Sus; EC 2.4.1.13), alkaline and soluble acid invertase (EC 3.2.1.26) and sucrose-phosphate synthase (SPS; EC 2.4.1.14) were compared at four developmental stages during seed filling. Among the four enzymes, only Sus activity was very high and strongly correlated with the starch concentration in the seed coat. Sucrose synthase catalyses the cleavage of sucrose in the presence of UDP into UDP-glucose and fructose. Sucrose synthase was purified from pea seed coats in a three-step protocol, consisting of diethylaminoethyl-Sephacel chromatography, gel filtration and affinity chromatography. The enzyme was characterized at the biochemical and molecular levels. Sucrose synthase exhibits biochemical properties which allow it to function in the direction of both sucrose cleavage and synthesis. The mass-action ratio of its four substrates was close to the theoretical equilibrium constant at the four developmental stages we studied. A labelling experiment on seed coats has shown that Sus activity is reversible in vivo and can produce 37% of neosynthesized sucrose in the seed coat cells (minimum value). It is concluded that Sus could play a central role in the control of sucrose concentration in the seed coat cells in response to the demand for sucrose in the embryo during the development of the seed.